Bokrug, the Great Water Lizard, is the god of the semi-amphibian Thuum'ha of Ib in the land of Mnar. The deity slept beneath the calm waters of a lake that bordered Ib and the city of Sarnath. When the humans of Sarnath cruelly slaughtered the populace of Ib and stole the god's idol, the deity was awakened.
Each year thereafter, strange ripples disturbed the otherwise placid lake. On the one-thousandth anniversary of Ib's destruction, Bokrug rose up and destroyed Sarnath, so utterly that not even ruins remained. Afterwards, the Thuum'ha recolonised Ib and thenceforth lived undisturbed.